System.xml Showing 404 Error – Magento Admin Fix

Below is my config.xml

<?xml version="1.0"?>
<config>
    <modules>
       <NameSpace_ModuleName>
          <version>1.0.0</version>
       </NameSpace_ModuleName>
    </modules>
</config>

Below is my adminhtml.xml

<?xml version="1.0"?>
<config>
    <acl>
    <resources>
        <all>
            <title>Allow Everything</title>
        </all>
        <admin>
            <children>
                <system>
                    <children>
                        <config>
                            <children>
                                <mymodulename>
                                    <title>Customer Config</title>
                                    <sort_order>80</sort_order>
                                </mymodulename>
                            </children>
                        </config>
                    </children>
                </system>
            </children>
        </admin>
    </resources>
</acl>
</config>

Below is my system.xml

<?xml version="1.0"?>
<config>
    <sections>
        <mymodule translate="label" module="mymodule">
            <class>separator-top</class>
            <label>Customer Config</label>
            <tab>customer</tab>
            <sort_order>100</sort_order>
            <show_in_default>1</show_in_default>
            <show_in_website>1</show_in_website>
            <show_in_store>1</show_in_store>
            <groups>
                <general translate="label" module="mymodule">
                    <label>Customer Configuration</label>
                    <sort_order>20</sort_order>
                    <show_in_default>1</show_in_default>
            <show_in_website>1</show_in_website>
                    <show_in_store>1</show_in_store>
                    <expanded>1</expanded>
                    <fields>
                        <active translate="label">
                            <label>Enable My Module</label>
                            <frontend_type>select</frontend_type>
                            <source_model>adminhtml/system_config_source_yesno</source_model>
                            <sort_order>1</sort_order>
                            <show_in_default>1</show_in_default>
                            <show_in_website>1</show_in_website>
                            <show_in_store>1</show_in_store>
                        </active>
                    </fields>
                </general>
            </groups>
        </mymodule >
    </sections>
</config>

I can see the section under Customer Tab, but when I click on it, it gives me 404 Not found error

My system.log is empty and shows nothing.

Please help to resolve.